How to Find a Gymnast's Speed at the Bottom of a Swing?

  • Thread starter Thread starter djherse
  • Start date Start date
AI Thread Summary
To find a gymnast's speed at the bottom of a swing using conservation of mechanical energy, the initial potential energy at the top equals the kinetic energy at the bottom. The gymnast's height of 1.0 m translates into potential energy, which converts entirely into kinetic energy at the lowest point. Mass cancels out in the energy equations, allowing the calculation to focus on height and gravitational acceleration. The discussion highlights confusion about setting up the equations and frustration with a lecture-free teaching method. Understanding the relationship between height and speed is crucial for solving the problem effectively.
djherse
Messages
10
Reaction score
0
Another Fine Gymnist problem ...

A gymnist is swinging on a high bar. The distance between his waist and the bar is 1.0 m, as the drawing shows.


At the top of the swing his speed is momentarily zero. ignoring friction and treating the gymnist as if all his mass is located at his waist, find his speed at the bottom of the swing.

I know it must have something to do with The conservation of mechanical energy however I am not sure how to set up both sides of the equation ? my algebra is a little ruff... I an lost here i know some stuff must cancell out but what ? it all can't cancell out Mass must cancell because it is not given to you but what else?
 
Physics news on Phys.org
bump...

On a side note my class is part of a physicis without lectures trial at me school we are the second class to be subjected to this new teaching style and it is horiable. We have Zero lectures and are told to determine equations on our own... the teacher will only answer questions we have. Our entire 3 hour class is spent working in a poorly written workbook...
 
djherse said:
A gymnist is swinging on a high bar. The distance between his waist and the bar is 1.0 m, as the drawing shows.


At the top of the swing his speed is momentarily zero. ignoring friction and treating the gymnist as if all his mass is located at his waist, find his speed at the bottom of the swing.

I know it must have something to do with The conservation of mechanical energy however I am not sure how to set up both sides of the equation ? my algebra is a little ruff... I an lost here i know some stuff must cancell out but what ? it all can't cancell out Mass must cancell because it is not given to you but what else?
What does the drawing show as his start point at the top of the swing, relative to the bottom of the swing? His speed at the bottom depends on how high up he starts.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top